Japanese by Example
Learning through examples in manga

あたし from a middle school girl

怪盗セイント・テール » Volume 1 » Page 85

Seira learns that Sayaka’s parents have forced her into an arranged marriage engagement, even though she likes Asuka Jr. Seira relays this to Meimi, saying if Saint Tail steals the gifted wedding veil from Sayaka’s home, the engagement will be called off. Before Meimi sets out, Seira confirms her intention to go through with the theft.

セイント・テール:
あたしが もし さやかちゃんだったら やっぱり そんな婚約(こんやく)はいやだもん!」
"If I were Sayaka-chan, sure enough, I'd hate such an engagement!"

Meimi often doesn’t use a personal pronoun due to context not calling for it, but when she does, she uses あたし both in narration and when with Seira. Most of Meimi’s female classmates use あたし as well.